ST. LOUIS COUNTY, Mo. (KSDK) - A 43-year-old Affton man pleaded guilty Thursday to allegedly providing alcohol to his 12-year-old stepson in the hours leading up to the boy's drowning death in the Meramec River.

According to the St. Louis County Prosecuting Attorney's Office, Todd Combs was charged with seven counts of second-degree endangering the welfare of a child in September 2012.

Christopher Marks went missing on Sunday, August 5 during a family outing to the Pacific Palisades conservation area. The family said Marks left around 7:30 p.m. to go rope swing on the river and was never seen from again.

His body was found in the river that Tuesday afternoon.

Marks' 15-year-old sister said at the time they had all been drinking.

Family members searched for Christopher Marks for hours after he disappeared before contacting police.

Search and rescue crews initiated a massive search for the boy in the following days. Authorities said Combs later discovered the body of his stepson several miles downstream while searching for the child.